With regard to the flavor of a green tea beverage, various inventions have been suggested from various viewpoints such as elevation of original odor and good taste of a green tea, or match to the taste of a consumer, and the like.
For example, Patent Document 1 discloses a method of manufacturing a water-soluble tea extract having flavor by adding enzymes to a tea extraction residue to hydrolyze it.
Patent Document 2 discloses a tea beverage that is obtained by two step extractions, i.e., extracting tea leaves in 80 to 100° C. hot water for 30 to 90 seconds, and then cooling the extract to 30 to 50° C. by adding cold water for 120 to 300 seconds, and then extracting it, wherein the tea beverage has high odor in the same degree as that of a high temperature-extracted tea beverage, and deep delicious taste and strong richness in the same degree as that of a low temperature-extracted tea beverage, and weak sourness.
Patent Document 3 discloses a low temperature extraction method of preventing generation of off flavor, which is so-called retort smell that occurs at the time of sterilization treatment.
Patent Document 4 discloses a method of mixing extraction liquids of refined green tea (Gyokuro tea) and deep-steamed tea for improving the flavor.
In addition, Patent Document 5 discloses a method of manufacturing a product that has a balance of delicious taste and aroma by using at least 2 or more kinds of extraction water of low temperature extraction and high temperature extraction.
Patent Document 6 suggests a method in which live tea leaves are roasted with an oven, whereby to boost the unique aroma of fired tea by heating and improve tea flavor.
Patent Document 7 suggests a method of manufacturing a green tea beverage packed in a tight-sealed container by blending an extraction of green tea, which is extracted by low temperature aqueous media such as 45 to 70° C. ion-exchanged water and the like from tea leaves (green tea), with an extract from live tea leaves extracted with hot water as it is, or a live tea leaf extract condensed and/or dried therefrom, which is intended to provide a green tea beverage packed in a tight-sealed container, which has freshly-brewed tea aroma and balanced flavor.
In addition, Patent Document 8 discloses a method of manufacturing a green tea beverage that is excellent in flavor, and has a good balance of aroma components, and has no unpleasant sediments, which comprises two-divided tea extraction steps, i.e., as one step, extraction of green tea leaves under pressure to obtain a pressure-extraction liquid (step A), and as another step, extraction of green tea leaves under ordinary pressure and fine filtration of this to obtain an ordinary pressure-extraction liquid (step B), and a mixing step of the pressure-extraction liquid and the ordinary pressure-extraction liquid obtained in each step in a mixing ratio that is determined on the basis of the weight of the raw tea leaves (step C).
Patent Document 9 discloses a method of manufacturing a green tea beverage that appropriately has unique green tea odor, delicious taste and richness, presents light greenish yellow of the color tone, and is translucent having no sediments even with long period storage, which comprises extracting a green tea with warm water at pH 8.0 to 10.0, and adjusting the extraction liquid to have pH 5.5 to 7.0 and 83 to 93% of turbidity as T % at 660 nm, respectively and then filling it into a package container and tight-sealing the package container.
In addition, Patent Document 10 discloses a method of manufacturing a tea beverage that is excellent in flavor, particularly excellent in nutritious taste, which comprises (i) a step of bringing tea leaves into contact with saturated steam, to promote opening of the tea leaves in the low temperature extraction step, (ii) a step of extracting the above-treated tea leaves with low temperature water, to obtain an extraction liquid, and (iii) a step of subjecting the above-mentioned extraction liquid to sterilization treatment.
Patent Documents 11 and 12 disclose a beverage packed in a container of which astringent taste and bitter taste are suppressed, which is obtained by blending a green tea extract containing high concentration of catechins with hydrocarbon in a suitable ratio.